On occasion it is necessary to attach articles to the roof of a structure. Such articles can include photovoltaic panels (solar panels), communication antennae, air conditioning equipment, heating equipment, and the like. The attachment is usually implemented by installing anchor devices on the roof, so that the article may be connected to the anchor devices. The anchor devices must necessarily penetrate the roof covering (such as shingles) and attach to a roof structural member such as a rafter. To minimize the possibility of water leaks, it is desirable to both minimize the number of roof penetrations and to ensure that the penetrations are water tight.